Bulky yarn and method of producing the yarn



Oct. 20, 1964 M. R. LIVINGSTON BULKY YARN AND METHOD OF PRODUCING THE YARN Original Filed July 15, 1958 United States Patent 3,153 316 BULKY YARN AND METHOD OF PRODUCING THE YARN Malcolm R. Livingston, Charlotte, N.C., assignor t0 Celanese Corporation of America, New York, N.Y., a corporation of Delaware 7 Original application July 15, 1958, Ser. No. 748,636, new Fatcnt No. 3,063,231, dated Nov. 13, 1962. Divided and this application May 15, 1962, Scr. No. 2i 3,671

10 Claims. .(Cl. 57-144) The present invention relates to bulked spun yarn in which a pre-formed continuous filament yarn or equivalent core is wrapped with discontinuous fibers of staple length with the staple fiber being substantially uniformly distributed along the length of the core and with the staple fiber being buckled to provide a lofty or bulky yarn of the core yarn type. The invention includes the bulked spun yarn of the core yarn type as well as methods for the production thereof.

In conventional drafting and spinning, staple fibers are carded into a loose web and then condensed into a roving or sliver about an inch or less in diameter with the fibers generally extending longitudinally. This is normally passed beneath rear rolls moving slowly and to forward rolls moving rapidly so that the roving or sliver is drawn or drafted to an extent corresponding to the difference in velocities between the forward and rear rolls. Thus, if the forward rolls move at a rate tending to advance the roving times faster than the rear rolls, the roving is elongated 15 fold. The elongated roving from the forward rolls is then twisted and taken up on a bobbin as a spun yarn.

In accordance with the invention, a pre-formed continuous filament yarn or spun yarn intended to constitute a core is passed together with at least one roving between the forward rolls of a drafting device. As employed herein the term roving has reference to a loose strand of staple fibers having either a low twist or no twist in which case it is sometimes called a sliver. The continuous fila ment yarn or spun yarn which is to constitute the core of the bulked yarn to be produced is supplied under tension so that the core is supplied at a linear speed of about 25 to 75 and preferably 40 to 60%, of the peripheral speed of the forward rolls so that the forward rolls are constantly slipping with respect to the core. In this manner, the staple fiber is caused to buckle and upon twisting there is produced a composite yarn in which the buckled staple fibers retain their distorted configurations and are wrapped around the core to form a bulky core yarn of lowered density and increased loft.

If the continuous core is supplied at a velocity greater than 75% of the peripheral speed of the front rolls substantially no bulking occurs. When the core is fed at 75% of the front roll speed, the yarn is shortened by 25% of the length that would normally be obtained if the core were fed at the same speed as the front roll surface. This 25% shortening in length results in 33% increase in weight per unit length. If the core is fed at only 25 of the peripheral speed of the front rolls, the length is shortened by 75%, resulting in 300% increase in weight per unit length. If the core is fed at less than 25% of the surface speed of the front rolls, spinning becomes difficult due to excessive breakage apparently resulting from too much twist in the core. Best results, with respect to bulk and ease of production, are obtained with the core fed at 40 to of the periperal speed of the front rolls. While the character and length of the staple fibers of the roving have some effect on the diameter of the composite product, i.e. its bulk, the indicated ranges generally produce the best results for any particular staple fiber.

The weighting on the forward rolls is maintained at a low level sufficient to draft the roving, and the tension applied to the core is such that slippage of the forward rolls with respect to the core may take place without breaking the core. The exact value of the tension which should not be exceeded will depend upon the nature and denier of the core and can readily be determined.

In accordance with another aspect of the invention, a plurality of rovings may be employed to supply discontinuous staple length fiber. However, the product which is produced cannot be untwisted to isolate ends corresponding to separate rovings and, hence, the product of the invention is not a plied yarn.

The invention also extends to an apparatus for producing the bulked spun core yarn, said apparatus including means to supply continuous filament or spun yarn to the forward rolls of a drafting device at a controlled rate less than the rate at which the forward rolls attempt to accept the continuous element so that the continuous element is constantly slipping with respect to the forward rolls. The apparatus is described and claimed in US. patent application Serial No. 748,636, filed July 15, 1958, now US. Patent No. 3,063,231, of which the present application is a division.

The invention will be more fully understood from the description which follows, taken in conjunction with the accompanying drawing in which:

FIG. 1 is a side elevation diagrammatically illustrating the procedure of the invention together with the equipment employed for carrying out the process on a schematic basis;

FIG. 2 is an enlarged diagrammatic side elevation illustrating the drafting device of the invention together with the structural features employed to modify this de vice to produce bulked spun yarn in accordance with the invention;

FIG. 3 is a diagrammatic plan View illustrating preferred apparatus for carrying out the invention with the continuous filament supply being shown in phantom; and

FIG. 4 is a diagrammatic view on an enlarged scale il lustrating the novel bulked spun yarn.

Referring more particularly to FIG. 1, the numeral 19 indicates a bobbin stand or creel in which a plurality of bobbins 11 are mounted in conventional manner to supply rovings 12. Bobbins 11 are rotatable so that when the roving 12 is pulled by the drafting device indicated generally by the numeral 13, the bobbins 11 will rotate to unwind the rovings 12.

The drafting device 13 is of conventional construction and includes an apron or endless band 14, a pair of control rolls 15 and 16, a weighted back roll which is desirably made of rubber and identified by the numeral 17, and a pair of rolls 18 and 19 upon which the endless band or apron 14 is mounted. In advance of the apron 14 is a pair of forward rolls 2%) and 21 which rotate at a greater velocity than the velocity of the endless band 14 for the back roll 17. Thus, the roving 12 is elongated or drafted between the back roll 17 and the forward rolls 20 and 21 to attenuate the same and to parallelize along the length of the roving the staple fiber constituting the same. The drafting can be similarly effected substituting any other conventional equipment for that shown, e.g. double aprons, multi-ro-ll systems, etc.

Mounted on a second creel, rack, or bobbin stand 22 are bobbins 23 which carry a continuous core element 24, the continuous core element being constituted by a continuous filament yarn or by a previously spun yarn. The core element 24 being a yarn is characterized by its high tensile strength which permits it to withstand far greater tension than can possibly be applied to roving 12 without disrupting the same. The core element 24 advances from the bobbin 23 through an aperture in the guide 25 and then to the forward rolls 20 and 21 of the drafting device 13, the rate of supply being controlled by the feed rolls 26 and 27. The food rolls 26 and 27 are driven by any suitable means which may, for example, be mechanical or electrical, at a rate to provide a peripheral velocity less than the velocity of the forward rolls 20 and 21.

By positively driving the feed rolls 26 and 27 at a peripheral speed which is less than the peripheral speed of the forward rolls 20 and 21, the core element 24 is advanced by the feed rolls and hence supplied to the forward rolls at a rate which is smaller than the rate which the forward rolls attempt to advance the core element. As a result, the forward rolls slip relative to the core element 24 and the staple fibers of the roving 12 are thrust forwardly along the length of the core element 24 to cause these staple fibers to be bent or buckled. The subsequent twisting serves to lock the buckled fibers in the positions they have assumed and the diameter of the composite yarn is effectively increased by the buckled staple fiber to provide a yarn of increased loft and lowered density.

Only a single bobbin 11 and roving are illustrated in FIG. 1. It will be understood that a plurality of rovings 12 may be withdrawn from separate bobbins and combined together in the same manner as would normally result in the production of a single yarn.

The composite yarn emerging from the forward rolls 2i) and 21 and which contains buckled staple length fiber associated with a continuous core element is then passed through an aperture in the yarn guide 28. The composite yarn is identified by the numeral 29 and it contains a continuous core constituted by the continuous filament or spun yarn 24 associated with the discrete fibers from the drafted roving 12 which have been buckled due to the difference between the peripheral speed of the forward rolls and the speed at which the core 24 is fed. The composite 29, after passing through the yarn guide 28 is led to a ring spinning device indicated generally by the numeral 31 in which the composite 29 is twisted to wrap the discrete fibers from the roving 12 around the core element 24 to securely anchor the staple fiber to the core and to fix and retain the buckled structure of the staple fiber in the bulked spun product which is produced. The spun composite 29, now identified by the numeral 30, is then taken up on the bobbin 33.

As will now be apparent, a conventional spinning frame is modified in accordance with the invention by the addition of a creel or equivalent means to supply continuous filament or spun yarn (the core element 24 and by the addition of means positively to feed the core element at a predetermined constant speed which is smaller than the speed at which the forward rolls attempt to receive and advance the core, i.e. smaller than the peripheral speed of the forward rolls. Additionally, suitable guides accurately to position the roving 12 and the core element 24 may be included in the structure which is employed.

If each spindle or take up bobbin 33 is fed from separate bobbins 11 and from separate bobbins 23 with the various rolls 15, 16, 17, 20, 21, 26 and 27 extending the length of the frame, the cost of modifying existing spinning frames would be substantial, though it is feasible to effect such modification.

Preferably, the invention is performed employing apr paratus as illustrated in FIG. 3 for the purpose of reducing the cost of modifying existing equipment.

Thus, small beams containing the same number of ends as are supplied on a standard spinning frame are prepared. The usual number of ends is about 240. In this manner, a sheet of yarns or rovings is supplied from a single beam. Referring more particularly to FIG. 3, the rovings 12 are supplied from the beam 40 as is indicated by the numeral 41. In the same manner, the core elements 24 are wound on the beam 42.

The core elements 24 supplied from the beam 42 may be supplied to the forward rolls 20 and 21 by the feed rolls 26 and 27 which are illustrated in FIG. 1 and the bulking action previously set forth attained in the same way. In this form of the invention, the core elements 24 are supplied at a controlled constant speed by directly predetermining the rate of rotation of the beam 42. Since controlled feeding is directly accomplished by means of the positive controlled rotation of the beam 42, the feed rolls 26 and 27 may be eliminated.

It will be appreciated that since all of the yarn ends supplied from the beam 42 (when this beam is driven) or supplied by the feed rolls 26 and 27 are simultaneously acted upon in the same manner, all of the bulked spun yarns which are produced by a given spinning frame will be bulked to a substantially identical extent.

While various means for positively controlling the rate of supply of the continuous core element 24 may be employed, FIGS. 2 and 3 of the drawing illustrate in diagrammatic form an illustrative mechanism for accomplishing this result. Thus feed rolls 26 and 27 (suitably geared together) or beam 42 are rotated at a uniform rate of speed by means of the belt 50 and pulley 51, the rate of rotation being controlled by the constant speed motor 52.

FIG. 4 diagrammatically illustrates the results which are produced in accordance with the invention. As will be seen, the core element 24 is substantially uniformly surrounded and wrapped within staple fiber 35. The staple fiber is buckled as indicated at 36, and the buckle is retained by the twist to provide a composite yarn 37 of increased effective diameter. Whereas in a conventional core yarn the staple fibers lie generally fiat against the core and are present in the minimum amount necessary just completely to hide the core, in the novel yarn the staple fibers are present in much greater proportion and their buckling produces a bulked product having a diameter many times greater than that of eitherthe core or the yarn which would be produced if the roving were drawn and twisted either alone or with a core fed at the same speed. The product is far more bulky than conventional core yarns having the same weight per unit length and composed of the same proportion of core and staple fibers.

The invention is illustrated in the table which follows, in which specific pre-formed yarns are combined with specific rovings in specific manner to produce bulked spun core yarns.

Table Spinning Frame Final Yarn Weighting Core Feed Set to Produce Produced Forward Velocity, Run No. Core Yarn Roving Rolls, Percent Ounces Front Roll Count Twist, Twist,

Speed Including t.p.i. Count t.p.i.

Core

1 100 denier high tenacity 2.0 Hank 3d 2 bright 5 50 /1 13 7.5/1 26 rayon. cellulose acetate. 2 do 2.0 Hank 2.5d 2 bright 7 40 8/1 4 3.2/1 10 cellulose triacetate. 3 100 denier nylon 2.0 Hank 3d 2 dull 6 70 18/1 12 12. 6/1 17.1

rayon. 4 200 denier cellulose ace- 2.0 Hank 3d 2" bright 3 70 6/1 5 4/1 7.1

cellulose acetate. 5 50 denier nylon do 3 25 40/1 5 10/1 20 It is to be understood that the foregoing detailed description is given merely by Way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. A method of producing a bulky yarn comprising supplying to a rotatable roll at least one roving of staple length fibers, supplying to said roll together with said roving a yarn to serve as a core, said supply of core being at a linear speed of about to 75% of the peripheral speed of said roll, such that said core is continuously under tension and said roll continuously slips relative thereto so that the fibers of said roving are caused to pile up and buckle about said core during slippage, and twisting the core and roving fibers issuing from said roll.

2. A method as recited in claim 1 in which said core is positively fed to said roll at controlled constant velocity.

3. A method as recited in claim 1 in which said core is constituted by a continuous filament yarn.

4. A method as recited in claim 1 in which said core is constituted by a spun yarn.

5. A method as recited in claim 1 in which said core is fed to said roll along with a single roving.

6. A method as recited in claim 1 in which said core is fed to said roll along with a plurality of rovings.

7. A method as recited in claim 1 in which the supply of said core is at a linear speed of about 40 to 60% of the peripheral speed f said roll.

8. A method of producing a bulky yarn comprising drafting between forward and rear rolls at least one roving of staple length fibers, supplying to said forward roll together with said roving a yarn to serve as a core, said supply of core being at a linear speed of about 25 to 75% of the peripheral speed of said forward roll, such that said core is continuously under tension and said forward roll continuously slips relative thereto so that the fibers of said roving are caused to pile up and buckle about said core during slippage, and twisting the core and roving fibers issuing from said forward roll.

9. A method as recited in claim 8 in which the supply of said core is at a linear speed of about 40 to of the peripheral speed of said forward roll.

10. A bulky core yarn comprising a continuous light compact core having staple length fibers wrapped about the same, said staple length fibers being distributed along the length of said core and being buckled to increase the bulk of said yarn, said buckled fibers being securely anchorcd to said core by twisting, said core and staple fibers being of the same composition, and said core being constituted by a continuous filament yarn.

References Cited in the file of this patent UNITED STATES PATENTS 2,309,095 Bry I an. 26, 1943 2,504,523 Harris et a1 Apr. 18, 1950 2,526,523 Weiss Oct. 17, 1950 2,588,361 Cooper Mar. 11, 1952 2,701,406 Bloch Feb. 8, 1955 2,869,967 Breen J an. 20, 1959 FOREIGN PATENTS 367,182 Great Britain Feb. 18, 1932 765,295 Great Britain Jan. 7, 1957 

1. A METHOD OF PRODUCING A BULKY YARN COMPRISING SUPPLYING TO A ROTATABLE ROLL AT LEAST ONE ROVING OF STAPLE LENGTH FIBERS, SUPPLYING TO SAID ROLL TOGETHER WITH SAID ROVING A YARN TO SERVE AS A CORE, SAID SUPPLY OF CORE BEING AT A LINEAR SPEED OF ABOUT 25 TO 75% OF THE PERIPHERAL SPEED OF SAID ROLL, SUCH THAT SAID CORE IS CONTINUOUSLY UNDER TENSION AND SAID ROLL CONTINUOUSLY SLIPS RELATIVE THERETO SO THAT THE FIBERS OF SAID ROVING ARE CAUSED TO PILE UP AND BUCKLE ABOUT SAID CORE DURING SLIPPAGE, AND TWISTING THE CORE AND ROVING FIBERS ISSUING FROM SAID ROLL. 